Pneumatic remote controlled release



July 28, 1942, R. L. LEVY 2,291,243

PNEUMATIC REMOTE CONTROLLED RELEASE Filed March 50, 1940 msmmkw Iii/9m&/ 4 a: z; z 1;

Patented July 28, 1942 UNITED STATES" PATENT OFFICE PNEUMATIC REMOTECONTBOILED RELEASE" a Ren Lucien Levy, Montrouge, France, asslgnor toSocit dlnventlons Aronautiques et Mcaniques STA M, Fribourg SwitzerlandApplication March 30, "1940, Serial at, 326,987 In France April 27, {939'1 Claim. (or le -2.3a)

It is known that some remote controls have to cause the substantiallyinstantaneous release of When such quick releases are obtained bypneumatic .means, it is the controlled member.

necessary for the action of the actuating fluid not to be delayed by thefriction or the sticking of fluid-tight packings provided in thepistonswhich exist in the pneumatic channels.

The invention has precisely forits object a'. pneumatic remote releasedevice which is free from these drawbacks which are prohibitive for someapplications, such, in particular, as gun controls.

Assuming, in order to give' a concrete idea,

that the actuating fluid is introduced, for the.

controlling action, into a cylinder that contains a piston connected tothe member to be controlled, the invention consists inusing a piston."which has no packings and'in only producing I the fluid-tightness ofthe piston in the cylinder V at the end of the stroke of the piston, bythe I contact of said piston with a fix'edplastic packing of anyappropriate type, carried by the end This relative fluid-tightness mustnevertheless be sufficient for the piston to be projected towards theopposite end 01 the cylinder when the actuating fluid under pressure isintroduced in front of the piston. In order to obtain this re- *sult; itis sufl'lcient for the periphery of the piston to -be provided with asystem of striations,

Y 'grooves or the like, which are capable of offering a suflicientobstruction to the passage of the compressed air, between the cylinderand the piston, 40

even in the absence of any packing on the latter. The figure or theaccompanying drawing shows diagrammatically a section of a firstembodiment of such a device in the case inwhich the inlet of thecompressed fluid (air, for example) iscflected in the compartmentopposit to the cylinder end through which the piston rod passes.

In this figure: l designates the cylinder; 2 a connection in-' tended tobe connected to a source of fluid under pressure. The rod 3 of thepiston 4 acts on the member to be controlled 5.

The piston is subjected to the action of a springli and its periphery,which is not provided I more or less deep, numerous and wide stria-.tions'l.

At.its Opposite end to the compartment 8, the

piston terminates in a kind of seat in relief 9.

On the inner wall of the end ID of the cylinder is -fixed a fluid-tightpacking ll of any appropriatenature.

' .When the pressure fluid is introduced into the compartment 8,- itprojects the piston in the direction or the'arrow towards the rear endl0.

'At the end of this stroke, the seat 9 comes into contact with thepacking II and is pushed firmly into the body'of said packing by theactual action of the actuating fluid, so that at this instant 'aperfectfluid-tightness is produced in th front compartment of the cylinder.

' -It has. therefore been possible to efiect the actuation of thecontrolled member 5 in a substantialIy instantaneous manner, since thrapidityJof the movement of the piston is not de- [pendent on anypacking. Owing to the fluidtightness, obtained, the controlled member 5is kept absolutely stationary, at the end of the stroke, in the positioninto which it has been Fig; 2 shows a modification of constructionapplicablein' the case which is the reverse of the previous one and inwhich th inlet 2 of the actuating fluid is effected in a compartment I2which is located on the same side as the end Ill,

through which passes the rod 3 of the piston 4 which ismovable in thecylinder I, the periphery or said piston-carrying, as before, a s stemof striationagrooves or their equivalent 1. a

In this embodiment, on the piston rod 3, where it passes through the andIII of the cylinder, there is fitted a movable sleeve l3, the innerpassage of which is provided with striations or their equivalent I whichproduce a. relative fluidtightness between the sleeve and the pistonrod.

0n the piston rod there is fixed, in an adjustable position, an abutmentmember I5 in which there is lodged an appropriate packing IS.

,A spring I] bears, on the one hand on the outer-wall of the and III, onthe other hand on a second abutment I8 which is also fixed on thepiston: rod. Said piston rod is attached at its end tothe member to becontrolled 5. The end IQ of th cylinder, which is opposite to the: inlettube 2, serves as a housing for a packing 21L :Two'circular'seat'srespectively -2l and Rare provided, one on the front face or the pistonI,

with any packing, is provided with a system of the other on the rearface 01' the sleeve l3, the

travel of the latter in the direction of the arrow 1 being moreoverlimited by a collar 23.

The mounting of the various elements of the device is such that thedistance a between the edge or the seat 22 and the fluid-tight packingIS with which it co-operates, is smaller than the distance D between theedge or the seat 2| and the fluid-tight packing 20.

The actuating fluid being introduced into the compartment l2 or thecylinder acts to push, on the one hand the piston 4 in the direction ofthe arrow I on the other hand the sleeve ii in the direction of thearrow f and presses the collar 23 against the end 10 if it wer notalready pressed thereagainst.

The fluid-tightness of the piston rod, relatively to the sleeve i3, issuiflcient to make this movement possible.

Owing to the fact that the distance a is smaller than the distance D,the packing i6, which is carried along with the piston rod, comes intocontact'with the seat 22 before the seat 2! has reached the packing 20.

In the last phase of the movement, the abutment I and the sleeve i3accompany the piston rod, the action of the actuating fluid having theefiect of producing absolute fluid-tightness between the seat 22 and thepacking it.

This action of the actuating fluid is still exerted to enhancefluid-tightnes from the instant when the seat 2i has come into contactwith the packing 20. At the end of the stroke of the piston, a perfectfluid-tightness is obtained in the compartment i2 of the cylinder. As inthe previous example, the actuation of the controlled member 5 hastherefore been effected very rapidly, since the piston 4 and its rod 3slide without appreciable friction within the cylinder l and the sleevei3. Similarly, at the end of the control stroke, the controlled member 5is kept stationary in its operative position.

In the two devices illustrated, it is sufllcient to connect theconnection 2 to the exhaust, for the springs, respectively 8 and i1, toreturn the piston and, with it, the controlled member, to their initialpositions.

An additional advantage of such a pneumatic remote controlled releaserests in the fact that the absence of packing enables the piston tooperate absolutely dry, a fact which is very important in the case inwhich the control is to be used at low temperatures, owing to the factthat in the known systems, the cold may cause the lubricating oils tocongeal and consequently bring about the locking of the piston.

While there is described what is at present considered to be thepreferred embodiments of this invention, it will be obvious to thoseskilled in the 'art that various changes and modifications may be madetherein without departing from the invention, and it is, therefore,aimed in the appended claim to cover all such changes and modificationsas fall within the true spirit and scope of the invention.

I claim:

A pneumatic remote controlled release, comprising a pneumatic cylinder,a piston without packing, connected to the member to be controlled, saidpiston being lodged in said cylinder, a pressure fluid inlet in thecompartment of said cylinder which is located on the same side as thepiston rod, a sleeve fltted on said rod, means for giving said sleeve arelative fluid-tightness with respect to said rod, a seat on saidsleeve, a transverse packing carried by said rod and adapted to beencountered by said seat, a seat carried by the face of the pistonopposite said rod, and a transverse packing flxed on the end of thecylinder opposite said rod, the arrangement being such that the seat ofthe sleeve is in contact with its packing before the seat of the pistoncomes into contact with its own packing.

RENE LUCIEN LEVY.

